Modern electronic systems are often required to accommodate multiple memory modules. Multiple memory modules can be installed in individual sockets on a mother board, but this takes up significant board space. Multi-row electrical connectors that mount multiple memory modules in a compact arrangement are known. However, these connectors have some drawbacks, particularly when considered for use in high speed operating systems.
U.S. Pat. No. 5,641,295 discloses an electrical connector having a pair of card-receiving slots for mounting a pair of memory modules on a mother board. The slots are stacked one above the other and oriented so that modules which are installed in the slots will reside parallel to the mother board in respective upper and lower planes. The slots are horizontally offset so that the lower module can be installed in and removed from its respective slot while the upper module remains in its respective slot. A problem with this connector is that contacts which extend from the upper slot to the mother board are relatively long which results in relatively high electrical inductance for these contacts. As operating speeds of electronic systems are increased, inductance becomes a significant problem. Further, this connector has a discrete contact associated with each input/output pad on each of the modules. This results in a very dense arrangement of contacts in the connector and a dense arrangement of leads extending from the connector for attachment to the mother board. There is a need to reduce the number of contacts in a multi-module electrical connector, and to reduce the inductance of the contacts in such a connector.